ML17053C761
| ML17053C761 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/28/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Rhode G NIAGARA MOHAWK POWER CORP. |
| References | |
| NUDOCS 8108060124 | |
| Download: ML17053C761 (12) | |
Text
Docket Ho. 50-410 JUL 2 8 f98f distribution Docket FIle LB'Schwencer NService BLynch OIE(3)
- Attraney, OELD bcc9 ACRS(16)
TERA TIC HSIC
'gHRC PDR L PDR t1r. Gerald K. Rhode Vice President System Project Manager 300 Erie Boulevard West
- Syracuse, Hew York 13202 Dear ter.
Rhode:
Subject:
Class 9 Accident Analyses in Report the thine Nile Point 2 Environme a0 The Commission's Statement of Interim Policy dated June 13, 1980,
{45 FR 40101),
states
- that, "Environmental Reports submitted by applicants for construction permits and operating licenses on or after July 1, 1981, should include a discussion of the environmental risks associated with accidents that follow the guidance herein."
Therefore, in accordance with this policy statement, we request that you consider the more severe kinds of very low probability accidents that are physically possible in environmental impact assessments required by the Hational Environmental Policy Act.
Such accidents are commonly referred to,as Class 9 accidents.
A copy of this statement is enclosed.
Your analyses of these accidents should be presented in the Environmental Report regarding Hine t1ile Point 2 at the time you tender your application for an operating license.
Sincerely, grighgQ Signed by Qpbart I TedeSCO Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
Enclosure:
Statement of Interim Policy
{45 FR 40101) cc w/encl:
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NRC FORM 318 (10-80) NRCM 0240 OFFIClAL RECORD COPY USGPO: 1981-888.980
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Niagara Mohawk Power Corporation ccs:
Eugene B. Thomas, Esq.
- LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Suite 1100 Washington,.
D.
C.
20036 Anthony Z. Roisman, Esq.
Natural Resources Defense Council 917 15th Street, N.
W.
Washington, D.
C.
20005 Mr. Richard Goldsmith Syracuse University College of Law E.. I. White Hall Campus
- Syracuse, New York 13210 T.
K. OeBoer, Director Technological Development Programs New York State Energy Office Agency Building 2
~
Empire State Plaza
- Albany, New York 12223
. Resident Inspector Nine Mile Point Nuclear Power Station P. 0.
Box 126
- Lycoming, New York 13093 Ezra I. Bialik Assistant Attorney General Environmental Protection Bureau New York State Department of Law 2 World Trade-Center New York, New York 10047
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10 CFR Parts 50 and 51 Nuclear Power Plant Accident Considerations Under the National Environmental Policy Act of 1969 AGKNGY'.S Nuclear Regulatory Commission AcT)oN: Statement of Interim Policy.
sUMMARY:The Nuclear Regulatory Commission [NRC) is revising its policy for considering the more severe kinds of very low probability accidents that are physically possible in environmental impact assessments required by the National Environmental Policy Act tNEPA). Such accidents are commonly referred lo as Claee o accidents.
scheme proposed by the Atomic Energy Commission (predecessor to NRC) in 1971 for purposes of implementing NEPA.'he March 28. 1919 accident at Unit 2 of the Three Mile Island nuclear plant has emphasized the need for changes in NRC policies regarding the considerations to be given to serious accidents from'an environmental as well as a safety point of view.
This statement of interim policy announces the withdrawal of the proposed Annex to Appendix D of 10 CFR Part 50 and the suspension of the rulemaking proceeding that began with the publication of that proposed Annex on December 1. 1911. It is the Commission's position that its Environmental Impact Statements shall include considerations of the site-specific environmental impacts attributable to accident sequences that
'Proposed as an Annex lo )0 CFR Patt SL Appendix D. )t) FR~). The Commission's NEPh.
imp)ament>nS rezui ~ lions were subset)uentty iiuty
)L )ttts) revised and recast as )0 CFR patt S) bul ~ t thai lime lhe Commission noted that "The Ptoposed Annex i~ slit) under considetanon
")9 FR 2dsttt.
lead to releases of tn".~ht)on and/or radioactive materiais. )ncludin)t
'equences that can result in Inadequate cooling of reactor fuel and to melting of the reactor core. In this regard. attention shall be given both to the probability of occurrence of such releases and to the environmental consequences of such releases. This statement of interim policy is taken in coordination with other ongoing safety-related activities that are directly relatt d to accident considerations in the areas of plant design. operational safety. siting policy.
and emergency p!arming. The Commission intends to continue the rulelnaking on this matter when new siting requirements and other safety related requirements incorporating accident considerations are in place.
GATEs) This. statement of interim policy is effective )une 13. 1980 Comment period expires Seplelnber 11. 1980.
AooREssss: The Commission intends the interim policy guidance contained herein to be immediately effective.
However. all interested persons who desire to submit written comments or suggestions for consideration in connection with this statement should send them to the Secretary of the Commission. U.S. Nuclear Reguiatofy Commission. Washington. D.C. 2055S.
Attention: Docketing and Service Branch.
FOR FURTHER INFORMATIOH CONTACT'.
Wayne Houston. Chief. Accident Evaluation Branch Office of Nuclear Reactor Regulation. U.S. Nuclear Regulatory Commission. Washington.
D.C. 20555. Telephone: (301) 492-/323.
SUPPLEMEHTARY )HFORMATIONe Accident Considerations in Past NEPA Reviews The proposed Annex to Appendix D of10CFR Part 50(hereafter the "Annex") was published for comment on December 1. 1911 by the (former)
Atomic Energy Commission. It proposed-to specify a set of standardized accident assumptions to be used in Environlnenta I Reports submi tte d by applicants for construction permits or operating licenses for nuclear power
" reactors. It also included a system for classifying accidents according to a graded scale of severity and probability of occurrence. Nine classes o'f accidents were defined. ranging from trivial to very serious. It directed that "for each class. except classes 1 and 9, the environmental consequences shall be evaluated as indicated.- Class 1 events were not to be considered because of their trivial consequences.
whereas in regard to Class 9 events: the Annex stated as follows:
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I The occurrtnccs in Class 9 involve stqutncts oi posiuislcd successive fsilurcs mort severe than those postulate d for ibt design basis for proetctivc systems and cngintcrcd scitiy ftsiurcs. Their consequences could bc severe. However. Ihc probability of their occeirrtnct is so smail Ihsi their tnvironmtnici risk is cxirtmciy Iow. Dticnst lie depth imuiiipitphysical bsrritrs). qvsiiiy sssursnct for dtsign.
msnufacturt. snd operation. continued survtiliantt snd testing. and conservative design are sii applied io provide eend msieeisin the rtquiitd high degree of cssursnct ihst pot tntial accidents in Ibis class srt. snd willrtmcin. sufficiently rtmotc in preibcbiliey Ihct the tnvironmtntal risk is cxertmtiy iow. For ibtst reasons. ii is noi ncttsssey lo discuss such tvtnls in sppiicsnis'nvironmtiitci Rtporls.
A footnote to the Annex stated:
Although this snntx refers io applicant's Environmtntat Reports. the current sssumpiions and oihtr provisions thereof are spplicsblt. cxctpi as iht tonitni may oehcrwist rtquirc. Io AEC draft and final Detailed Sisicmtnis.
During the public comment period that followed publication of the Annex a number of criticisms of Ihe Annex were received. Principal among these were the following:
(1) The philosophy of prescribing assumptions does not lead to objective analysis.
(2) It failed to Ireat the probabilities of accidents in any but the most general way.
(3) No supporting analysis was given Io show that Class 9 accidents are sufficiently low in probability thai their consequences in terms of environmental risks need not be discussed.
(4) No guidance was given as to how accident and norma! releases of radioactive effluents during plant operation should be factored into the cost. benefit analysis.
(5) The accident assumptions are not generally applicable to gas cooled or liquid metal cooled reactors.
(6) Safety and environmental risks are not essentially different considerations.
Neither the Atomic Energy Commission nor the NRC.took any further action on this rulemaking except in 1974 when 10 CFR Part 51 was promulgated. Over the intervening years the accident considerations discussed in Environmental Impact Statements for proposed nuclear power plants reflected the guidance of the Annex with few txceptions. Typically. the discussions of accident consequences through Class 8 (design basis accidents) for each case have reflccted specific sile characteristics associated with meteorology (the dispersion of releases of radioactive material into the atmosphere).
the actual population within a 50.mile radius of Ihe plant. and some differences between boiling water reactors (BlVR) and pressurized water reactors (PWR). Beyond these few specifics. the discussions have reiterated the guidance of the Annex and have relied upon the Annex's conclusion that the probability of occurrence of a Class 9 event is too low to warrant consideration.
a conclusion based upon generally staled safety considerations.
With the publication of the Reactor Safety Study (NASH-1400), in draft form in August 1974 and final form in October 1975. Ihe accident discussions in Environmental Impact Statements began to refer to this first detailed study of the risks associated with nuc)ear power plant accidents. particularly events which can lead to the melting of.
the fuel inside a reactor.t The references to this study were in keeping with the intent and spirit of NEPA -to disclose" relevant information. but it is obvious that WASH-1400 did not form the basis for the conclusion expressed in the Annex in 1971 that Ihe probability of occurrence of Class 9 events was too low to warrant their (site-specific) consideration under NEPA.
The Commission's staff has. however.
identified in certain cases unique circumstances which it felt warranted more extensive and detailed consideration of Class 9 events. One of these was the proposed Clinch River Breeder Reactor Plant (CRBRP). a liquid metal cooled fast breeder reactor very different from the more conventional light water reactor plants for which the safety experience base is much broader.
In the Final Environmental Statement for the CRBRP.s the staff included a discussion of the consideration it had given Io Class 9 events.
'n the early site review for the Perryman site, the staff performed an informal assessment of the relative differences in Class 9 accident consequences among the alternative sites. (SECY-78-'137)
In the case of the application by Offshore Power Systems to manufacture floating nuclear power plants. the staff judged that the environmental risks of some Class 9 events warranted special consideration. The special circumstances were Ihe potentially serious consequences associated with water (liquid) pathways leading to radiological exposures ifa molten reactor core were to fall into the water s ii I~ of inececse ihsi ihc Rcsceor Ssfciy Seudy never ectcrs eo nor uses ihc icim "Ctsss 0 sccidcne" slehovth this tenn is comesonty used ss loosely cquwslcni eo ~ core mcil sccidcnl.
s NUREC-oist. Fcbevs ey tsyy.
body on which thc plant floats. Here Ihe staff emphasized its focus on risk to the environment but did not.find that the probability of a core. melt event occurring in the first place was essentially any different than for land-based plant. In its Memorandum and Order In Ihe Matter of Offshore Power Systems.s the Commission concurred in the staffs judgment. Thus, the Reactor Safety Study and NRC experience with these cases has served to refocus attention on the need to reemphasize that environmental risk entails both probabilities and consequences.
a point that was made in the publication of the Annex. but was no! given adequate emphasis.
In July19.c the&RC commissioned a
Risk Assessment Review Group "to clarify the acfiievemenls and limitations of the Reactor Safety Study.- One of the conclusions of this study. published in September 1978, as NUREG/CR~OO,
-Risk Assessment Review Group Report to Ihe U.S. Nuclear Regulatory Commission,- was that -The Review Group was unable Io determine whether the absolute probabilities of accident sequences in WASH-1400 are high or low. but believes that the error bounds on those estiir ates are in general.
greatly understated." This and other
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findings of the Review Group have also subsequently been referred to in Environmental Impact Statements.
along with a reference to the Commission's policy statement on the Reactor Safety Stude in light of the Risk Assessment Review Group Report. published on January 18. 1979. The Commission's statement accepted the find!ngs of the Review Group. both as to the Reactor Safety Study's achievements and as to its limitations.
A few Draft Environmental Statements have been published subsequent to the Three Mile Island accident. These were for conventional land-based light water reactor plants and continued to reflect the past practice with respect to accidents at such plants. but noted that the experience gained I'rom the Three Mile Island accident was not factored into the discussion.
Our experience with past NEPA reviews of accidents and the TMI accident clearly lebds us to believe that a change is needed.
Accordingly, the proposed Annex to Appendix D of 10 CFR Part 50. published on December i. 1971, is hereby withdrawn and shall not hereafter be used by applicants nor by the staff. The reasons for the withdrawal are as follows:
'Dochce!'o. STN ~sr. Scplcsebcr lc. )iirs.
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- 1. The Annex proscribes consideration of the kinds of accidents IC)ass 9) that. according to the Reactor Safely Study. dominate the accident risk.
- 2. The definition of Class 9 accidents in the Annex is not sufficiently precise to warrant its further use in Comm('ssion policy. rules. and regulations, nor as a decision criterion in agency practice.
- 3. The Annex's prescription of assumptions to be used in the analysis of the environmental consequences of accidents does not contribute lo objective consideration.
- 4. The Annex does nol give adequate consideration lo the detailed treatment ofmeasures taken to prevent and to mitigate the consequences of accidents in Ihe safety review of each applicatioa.
The classification of accidents proposed in that Annex shall no longer be used. In ils place the following in(erirn guidance is given for the treatment of accident risk considerations in NEPA reviews.
Accident Considerations ia Fulure NEPA Reviews II is lhe position of Ihe Commission that its Environmental Impact Slalemenls, pursuanl to Section 102(c)[i) of the National Environmental Policy Act of!969. shat) include a reasoned consideration of the environmental risks (impacts) attributable lo accidents at the particular facilityor facilities within the scope of each such statement. In the analysis and discussion of such risks.
approximately equal attention shall be given to the probability of occurrence of releases and lo the probability of occurrence of the environmental consequences of those releases.
Releases refer to radiation and/or radioactive materials entering environmental exposure pathways.
Inctudint( air. water. and ground water.
Events or accident sequences that leail tu releases shall include but nol be limited lo those that can reasonably be expected lo occur. In.plant accident sequences that can lead to a spectrum of releases shall be discussed and shall include sequences that can result in inadequate cooling of reactor fuel and to melting of Ihe reactor core. The extent to, which evenls arising from causes external to the plant which are considered possible contributors to the risk associated with (he particular plant shall also be discussed. Detailed quan(itative considerations that form the basis of probabilistic estimates of releases need not be incorporaled in the Environmental Impact Statements but shall be referenced therein. Such references shall include. as applicable.
reports on safety evaluations.
The environmental consequences of releases whose probability of occurence has been estimated shall also be discussed in probabilistic terms. Such consequences shall be characterized in terms of polen'tial radiological exposures to individuals. to population groups..and. where applicable. (o biota.
Heallh and safety risks that may be associated with exposures lo people shall be discussed in a manner lhat fairlyreflects the current.state of know)edge regarding sacs risks.
Socioeconomic impacts thai might be associated with emergency tneasures during or following an accident should also be discussed. The environmental risk ofaccitients should also be compared to and contrasted with radiological risks associated with nortnal and anticipated operalional releases.
In protnulga ling this interim guidance.
the Commission is aware that there are and willlikely remain for some time lo come many uncertainties in the application of risk assessment
- methods, and it expects that its Environmental Impac! Statements willidentify major uncertainties in its probabilislic estimates. On the other hand the Comtnission be)ieves that the state of the art is sufficiently advanced that a beginning should now be made in the use of these methodologies in the regutatory process. and that such use willrepresent a contructive and rational forward step in the discharge of its reponsibilities.
lt is the intent of the Commission in issuing this Statement of Interim Policy that Ihe staff wiltinitiate treatments of accident considerations. in accordance with lhe foregoing guidance. in its ongoing NEPA reviews. i.e. ~ for any proceeding al a licensing stage where a Final Environmental impact Statement has not yet been issued. These new treatments, which willlake into account sign)ftcant site-and plant-specific features. willresult, in more detailed discussions of accident risks than in previous environmental slalements.
particularly for those re)ated lo convenlional light water plants at land-based sites. It is expected that these revised treatments willlead to conc) usions regarding the environmental risks of accidents similar to those that would be reached by a continuation of current practices. particularly for cases invo)ving special circumstances where Class 9 risks have been considered by lhe staff. as described above. Thus, this change in policy is not to be construed as any lack of confidence in conclusions regarding the environmental risks of accidents expressed in any previously issued Statemenls. nor. absent 8
showing of similar'special circumstances.
as a basis for opening.
reopening. or expanding any previous or ongoing proceeding.'owever. it is also the intent of the Commission that the staff lake steps lo identify additional cases that might warrant early consideration of eilher additional features ot other actions which would prevent or mitigate the consequences of serious accidents.
Cases for such consideration are those for which a Final Environtnental Slalemenl has already been issued al the Construction Permit stage but for which the Operating License review stage has not yet been reached. In carrying out this directive. the staff should consider relevant site features.
including population density. associated with accident risk in comparison to such features at presently operating plants.
Staff should also consider the likelihood thai substantive changes in plant design features which may compensate further for adverse site features may be more easily incorporated in plants when construction has not yet progressed very far.
Environmental Reports submitted by applicants for construction permils and for operating licenses on or after July 1.
1980 should include a discussion of the environmental risks associated with accidents that follows the guidance given herein.
Related Policy Matters Under Consideration ln addition to its responsibilities under NEPA. the NRC also bears responsibility under the Atomic Energy Act for (he protection of the public health and safety from the hazards associaled with the use of nuclear energy. Pursuant to this responsibility Ihe Commission notes that there are currently a number of ongoing activities being considered by the Commission and its staff which intimately relate to the -Class 9 accident-question and which are eilher the subject of current rulemaking or are candidate subjects for rulemaking.
On December 19. 1979 the Comtnission issued for public comment 4 a proposed rule which would significantly revise its requirements In 10 CFR Part 50 for emergency planning for nuclear power plants. One of the considerations in this rulemakin'g was
'Commissioners Cilins'ky and Bradford disazree with the inclusion o( the preccdins iwo sentences.
They feet that they arc absolutely inconsi ~ieni with an even handed reappraisal o( tbc former.
cnoneous position on Class tt acodcnts.
ssa FR rSldr.
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the potential consequences of Class 9 accidents in a generic sense.'.:
August 1979. pursuant to the.
Commission's request.
a Siting Policy Task Force made recommendations with respect to possible changes in NRC reactor siting policy and criteria.'urrenlly set forth in 10 CFR Part 100. As stated therein. ils recommendations were made to accomplish (among others) Ihe foI)otving goal:
To take into consideratton in siting Ihe risk associated with accidents beyond lhc design basis IClass 9) by establishing population densitv and distribution criteria.
This matter is currenlly before the Commission.
This and other recommendations that have been made as a result of the investigations into the Three Mile Island accidenl are currently being brought togelher by Ihe Commission's staff in the form of proposed Action Plans.'mong other matters. these incorporate recommendations for rulemaking related to degraded core cooling and core melt accidents. The Commission expects to issue decisions on Ihese Action Plans in the near future. Il is the Commission's policy and intent to devole NRC's major resources lo matters which the Commission believes willmake existing and future nuclear power plants safer.
and to prevent a recurrence of Ihe kind of accident that occurred at Three Mile Isiand. In the interim. however. and pending completion of rulemaking activilies in Ihe areas of emergency planning. siting criteria. and design and operational safely. all of which involve considerations of serious accident potential. the Commission finds il essenlial lo improve ils procedures for describing and disclosing to the public the basis for arriving at conclusions regarding the environmental risks due to accidents at nuclear power plants. On completion of the rulernaking activities in these areas. "nd based also upon the experience gained with this stalemenl of interim policy and guidance. the Commission intends lo pursue possible changes or additions to 10 CFR Part 51 to codify ils position on Ihe role of accident risks under NEPA.
'Cf NUREC-tat>r>."Ptsnntng ass>s for the Deveiopment of St ~ te snd Local Covemment Rsd>olos>csl Emergency Response Plans ln Support of L>ght Wstcr Nuclcsr Power Picots." November tera.
'NUREC-ones. "Rcpon of thc S>ting Pohcy Task Force." August ttrra.
'Draft NURECao60.
Act>on Plans for lmptcmentmg Recommendst>ons of thc President s
Commis ~>on sod Other Studies of the Thtl 2 Acmocnt." December 10. ttlrQ.
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